These studies were performed to understand the mechanism of ionic current block by general anesthetics using voltage clamp and internal perfusion techniques on squid giant axons. So far we have tested five general anesthetics, namely halothane, penthrane, trichloroethylene, fluroxene and ketamine. All these anesthetics change the apparent reversal potential to peak transient current towards hyperpolarization. This finding may generally apply to other general anesthetics, and thus can be of great importance in understanding the molecular mechanism of action of general anesthetics. BIBLIOGRAPHIC REFERENCE: Brij Bhushan Shrivastav (1976). Mechanism of ketamine actions on the electrical properties of squid axon membrane. Fed. Proc. 35, 403.